getElementByClass().setAttribute doesn't work

Question

why when i write

document.getElementByClass(\'home1\').setAttribute(\'style\', \'background-image:url(img/red_menu.PNG);\');

it doesn\'t wo

Answer 1

If you have only one classname in your entire HTML file, then you could also use

  document.getElementsByClassName('navbar-nav')[0].setAttribute('id', 'navbar-toggle');